/**
 * ═══════════════════════════════════════════════════════════
 *  Studies Learning — « Le Parcours du Créateur »
 *  Section : Comment devenir formateur ?
 *  Concept  : Timeline Cinématographique
 *  Auteur   : Antigravity / Studies Learning Design System
 * ═══════════════════════════════════════════════════════════
 *
 *  CONCEPT VISUEL :
 *  ───────────────
 *  Chaque étape est un "chapitre" dans le voyage du formateur.
 *  Une ligne de progression s'anime en temps réel au fil du scroll.
 *  La colonne droite affiche une image + overlay de stats qui
 *  se transforme au fur et à mesure que l'utilisateur lit les étapes.
 *  Les numéros de chapitre sont monumentaux, comme au cinéma.
 *
 *  PALETTE :
 *  ─────────
 *  Fond           → #f9fbfd  (blanc bleuté, harmonisé site)
 *  Accent principal → #0047ff  (bleu Studies Learning)
 *  Accent doux    → #a6c8ff  (bleu poudré, surbrillances)
 *  Ligne / Track  → #dce8f8  (bleu très clair)
 *  Texte          → #0f172a  (quasi-noir bleuté)
 *  Sous-texte     → #64748b  (gris ardoise)
 */

/* ─── Variables ─────────────────────────────────────────── */
.studies-p-df-how-it-works {
  --df-bg: #f9fbfd;
  --df-accent: #0047ff;
  --df-accent-soft: #a6c8ff;
  --df-accent-glow: rgba(0, 71, 255, 0.12);
  --df-track: #dce8f8;
  --df-text: #0f172a;
  --df-subtext: #64748b;
  --df-card-bg: rgba(255, 255, 255, 0.72);
  --df-step-duration: 0.55s;
  --df-ease: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ─── Section wrapper ───────────────────────────────────── */
.studies-p-df-how-it-works {
  background: linear-gradient(180deg, #ffffff 0%, var(--df-bg) 100%);
  padding: 4rem 2rem 9rem !important;
  overflow: hidden;
  position: relative;
}

/* Subtle grain texture overlay */
.studies-p-df-how-it-works::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.025'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
}

/* ─── Section header ────────────────────────────────────── */
.studies-p-df-how-it-works .studies-p-df-section-header {
  text-align: center;
  margin-bottom: 5rem;
  position: relative;
  z-index: 1;
}

.studies-p-df-how-it-works .studies-p-df-section-header h2 {
  font-family: "Plus Jakarta Sans", "Outfit", sans-serif;
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 300;
  color: var(--df-text);
  letter-spacing: -0.02em;
  margin-bottom: 0.6rem;
}

.studies-p-df-how-it-works .studies-p-df-section-header h2 strong {
  font-weight: 700;
  color: var(--df-accent);
}

.studies-p-df-how-it-works .studies-p-df-section-header p {
  font-size: 1rem;
  color: var(--df-subtext);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 400;
}

/* Decorative line under header */
.studies-p-df-how-it-works .studies-p-df-section-header::after {
  content: "";
  display: block;
  width: 48px;
  height: 2px;
  background: var(--df-accent-soft);
  margin: 1.5rem auto 0;
  border-radius: 2px;
}

/* ─── Two-column layout ─────────────────────────────────── */
.studies-p-df-steps-wrapper {
  display: grid;
  grid-template-columns: 1fr 0.75fr;
  gap: 6rem;
  max-width: 1200px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
  align-items: start;
}

/* ─── LEFT COLUMN : Steps ────────────────────────────────── */
.studies-p-df-steps-column {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* The animated vertical track line */
.studies-p-df-steps-column::before {
  content: "";
  position: absolute;
  left: 28px;
  top: 30px;
  bottom: 30px;
  width: 1px;
  background: var(--df-track);
  z-index: 0;
}

/* Animated progress fill */
.studies-p-df-track-progress {
  position: absolute;
  left: 28px;
  top: 30px;
  width: 1px;
  height: 0%;
  background: linear-gradient(
    180deg,
    var(--df-accent) 0%,
    var(--df-accent-soft) 100%
  );
  z-index: 1;
  transition: height 0.6s var(--df-ease);
  border-radius: 1px;
}

/* ─── Single Step ─────────────────────────────────────────── */
.studies-p-df-premium-step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 0 2rem;
  padding: 0 0 3rem 0;
  position: relative;
  opacity: 0;
  transform: translateX(-20px);
  transition:
    opacity 0.5s var(--df-ease),
    transform 0.5s var(--df-ease);
}

/* ─── Number bubble ─────────────────────────────────────── */
.studies-p-df-step-bullet {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-shrink: 0;
}

/* The circle node */
.studies-p-df-step-bullet-dot {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: #fff;
  border: 1.5px solid var(--df-track);
  display: flex;
  align-items: center;
  justify-content: center;
  transition:
    background var(--df-step-duration) var(--df-ease),
    border-color var(--df-step-duration) var(--df-ease),
    box-shadow var(--df-step-duration) var(--df-ease),
    transform var(--df-step-duration) var(--df-ease);
  position: relative;
}

/* Giant ghost number behind the dot */
.studies-p-df-step-ghost-num {
  position: absolute;
  font-family: "Plus Jakarta Sans", "Outfit", sans-serif;
  font-size: 8rem;
  font-weight: 800;
  color: rgba(0, 71, 255, 0.04);
  line-height: 1;
  left: -10px;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
  transition: color var(--df-step-duration) var(--df-ease);
  letter-spacing: -0.04em;
  z-index: -1;
  user-select: none;
}

/* Ordinal number inside dot */
.studies-p-df-step-num-label {
  font-family: "Plus Jakarta Sans", "Outfit", sans-serif;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--df-subtext);
  letter-spacing: 0.06em;
  transition: color var(--df-step-duration) var(--df-ease);
  line-height: 1;
}

/* ─── Step body (right side) ────────────────────────────── */
.studies-p-df-step-body {
  padding-top: 12px;
}

/* Step title row */
.studies-p-df-step-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  gap: 1rem;
  padding-bottom: 0;
  border: none;
  background: transparent;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.studies-p-df-step-title-wrap {
  flex: 1;
}

.studies-p-df-step-title-wrap h3 {
  font-family: "Plus Jakarta Sans", "Outfit", sans-serif;
  font-size: 1.15rem;
  font-weight: 500;
  color: var(--df-text);
  margin: 0;
  line-height: 1.35;
  transition: color var(--df-step-duration) var(--df-ease);
  letter-spacing: -0.01em;
}

/* Toggle button */
.studies-p-df-step-toggle {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1.5px solid var(--df-track);
  background: transparent;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition:
    background var(--df-step-duration) var(--df-ease),
    border-color var(--df-step-duration) var(--df-ease),
    transform var(--df-step-duration) var(--df-ease);
  position: relative;
  padding: 0;
}

/* Plus icon via spans */
.studies-p-df-step-toggle span {
  position: absolute;
  background: var(--df-subtext);
  border-radius: 2px;
  transition:
    background var(--df-step-duration) var(--df-ease),
    transform 0.35s var(--df-ease),
    opacity 0.3s ease;
}

.studies-p-df-step-toggle span:first-child {
  width: 12px;
  height: 1.5px;
}

.studies-p-df-step-toggle span:last-child {
  width: 1.5px;
  height: 12px;
}

/* Expanded content */
.studies-p-df-step-content {
  max-height: 0;
  overflow: hidden;
  transition:
    max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1),
    padding-top 0.4s ease;
}

.studies-p-df-step-content p {
  font-size: 0.95rem;
  color: var(--df-subtext);
  line-height: 1.8;
  margin: 0;
  padding-top: 1rem;
  font-weight: 300;
}

/* Subtle tag showing step keyword */
.studies-p-df-step-tag {
  display: inline-block;
  margin-top: 0.8rem;
  padding: 0.3rem 0.85rem;
  background: rgba(0, 71, 255, 0.07);
  color: var(--df-accent);
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  opacity: 0;
  transform: translateY(6px);
  transition:
    opacity 0.4s ease 0.15s,
    transform 0.4s ease 0.15s;
}

/* ───────────────────────────────────────────────────────── */
/* Active / hover states */
/* ───────────────────────────────────────────────────────── */

/* Hover on non-active step */
.studies-p-df-premium-step:not(.is-active):hover .studies-p-df-step-bullet-dot {
  border-color: var(--df-accent-soft);
  box-shadow: 0 0 0 6px rgba(166, 200, 255, 0.15);
  transform: scale(1.05);
}

.studies-p-df-premium-step:not(.is-active):hover
  .studies-p-df-step-title-wrap
  h3 {
  color: var(--df-accent);
}

.studies-p-df-premium-step:not(.is-active):hover .studies-p-df-step-toggle {
  border-color: var(--df-accent-soft);
}

/* Active step */
.studies-p-df-premium-step.is-active .studies-p-df-step-bullet-dot {
  background: var(--df-accent);
  border-color: var(--df-accent);
  box-shadow:
    0 0 0 6px rgba(0, 71, 255, 0.1),
    0 8px 25px rgba(0, 71, 255, 0.22);
  transform: scale(1.08);
}

.studies-p-df-premium-step.is-active .studies-p-df-step-num-label {
  color: #fff;
}

.studies-p-df-premium-step.is-active .studies-p-df-step-ghost-num {
  color: rgba(0, 71, 255, 0.08);
}

.studies-p-df-premium-step.is-active .studies-p-df-step-title-wrap h3 {
  color: var(--df-accent);
  font-weight: 600;
}

.studies-p-df-premium-step.is-active .studies-p-df-step-toggle {
  background: var(--df-accent);
  border-color: var(--df-accent);
  transform: rotate(45deg);
}

.studies-p-df-premium-step.is-active .studies-p-df-step-toggle span {
  background: #fff;
}

.studies-p-df-premium-step.is-active .studies-p-df-step-tag {
  opacity: 1;
  transform: translateY(0);
}

/* ─── RIGHT COLUMN : Signature Image ───────────────────── */
.studies-p-df-image-column {
  position: sticky;
  top: 8rem;
  height: 480px;
  overflow: visible;
}

.studies-p-df-signature-image {
  position: relative;
  width: 100%;
  height: 100%;
  border-radius: 28px;
  overflow: hidden;
  box-shadow:
    0 4px 6px rgba(0, 0, 0, 0.04),
    0 24px 60px rgba(0, 0, 0, 0.1),
    0 60px 100px rgba(0, 0, 0, 0.06);
}

/* Slight right-edge bleed */
.studies-p-df-signature-image::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 28px;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.12);
  z-index: 3;
  pointer-events: none;
}

.studies-p-df-signature-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(25%) contrast(1.04);
  transition:
    transform 1s ease,
    filter 0.6s ease;
  transform-origin: center center;
}

/* Gradient overlay — bottom fade to bg color */
.studies-p-df-image-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    160deg,
    rgba(249, 251, 253, 0) 40%,
    rgba(249, 251, 253, 0.6) 100%
  );
  z-index: 2;
  pointer-events: none;
}

/* Floating badge on image */
.studies-p-df-image-badge {
  position: absolute;
  bottom: 2rem;
  left: 2rem;
  right: 2rem;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: 18px;
  padding: 1.2rem 1.5rem;
  z-index: 4;
  display: flex;
  align-items: center;
  gap: 1rem;
  box-shadow:
    0 2px 4px rgba(0, 0, 0, 0.04),
    0 12px 32px rgba(0, 0, 0, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.6);
  transform: translateY(10px);
  opacity: 0;
  transition:
    opacity 0.5s ease,
    transform 0.5s ease;
}

.studies-p-df-image-badge.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.studies-p-df-badge-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--df-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1.3rem;
  color: #fff;
}

.studies-p-df-badge-text {
  flex: 1;
  min-width: 0;
}

.studies-p-df-badge-text strong {
  display: block;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--df-text);
  line-height: 1.2;
  margin-bottom: 0.2rem;
}

.studies-p-df-badge-text span {
  font-size: 0.8rem;
  color: var(--df-subtext);
  font-weight: 400;
}

/* Step-specific badge data */
.studies-p-df-badge-data {
  display: none;
}

/* Decorative dot grid (top-right corner of image) */
.studies-p-df-dot-grid {
  position: absolute;
  top: -1.5rem;
  right: -1.5rem;
  width: 80px;
  height: 80px;
  z-index: 5;
  pointer-events: none;
  opacity: 0.55;
}

.studies-p-df-dot-grid svg circle {
  fill: var(--df-accent-soft);
}

/* ─── Animations ────────────────────────────────────────── */
@keyframes df-fadeInLeft {
  from {
    opacity: 0;
    transform: translateX(-20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes df-pulse-ring {
  0% {
    transform: scale(1);
    opacity: 0.6;
  }
  100% {
    transform: scale(1.6);
    opacity: 0;
  }
}

/* Pulse ring on active node */
.studies-p-df-premium-step.is-active .studies-p-df-step-bullet-dot::before {
  content: "";
  position: absolute;
  inset: -8px;
  border-radius: 50%;
  border: 1px solid var(--df-accent-soft);
  animation: df-pulse-ring 2s ease-out infinite;
}

/* ─── RESPONSIVE ────────────────────────────────────────── */
@media (max-width: 1024px) {
  .studies-p-df-steps-wrapper {
    grid-template-columns: 1fr;
    gap: 4rem;
  }

  .studies-p-df-image-column {
    position: relative;
    top: auto;
    height: 360px;
    order: -1; /* Image above on tablet */
  }

  .studies-p-df-signature-image {
    border-radius: 20px;
  }
}

@media (max-width: 768px) {
  .studies-p-df-how-it-works {
    padding: 5rem 1.25rem 6rem !important;
  }

  .studies-p-df-how-it-works .studies-p-df-section-header {
    margin-bottom: 3rem;
  }

  .studies-p-df-image-column {
    height: 280px;
  }

  .studies-p-df-premium-step {
    grid-template-columns: 44px 1fr;
    gap: 0 1.2rem;
    padding-bottom: 2rem;
  }

  .studies-p-df-steps-column::before {
    left: 21px;
  }

  .studies-p-df-track-progress {
    left: 21px;
  }

  .studies-p-df-step-bullet-dot {
    width: 44px;
    height: 44px;
  }

  .studies-p-df-step-ghost-num {
    font-size: 5.5rem;
  }

  .studies-p-df-step-title-wrap h3 {
    font-size: 1.05rem;
  }

  .studies-p-df-image-badge {
    bottom: 1rem;
    left: 1rem;
    right: 1rem;
    padding: 1rem;
  }
}

@media (max-width: 480px) {
  .studies-p-df-image-column {
    height: 220px;
  }

  .studies-p-df-steps-wrapper {
    gap: 2.5rem;
  }
}